The invention described herein may be manufactured and used by or for the Government of the United States of America for governmental purposes without payment of any royalties thereon or therefor.
This invention pertains to the field of flares, and more particularly to the construction of the flare case for naval decoy flares for the protection of aircraft and other potential targets from hostile missiles and aircraft that target infrared energy. This field includes explosive cases of infrared flares, illumination flares or flares designed to emulate the infrared, visible light and or electromagnetic signature of an airborne missile, space craft or aircraft.
Naval aviation has always had special requirements for aircraft and weapon systems and their countermeasure equipment not required by the United States military counterpart systems in the other services. These increased requirements, result in part from the tremendous forces generated by aircraft operating from a carrier deck. In aircraft operating from a carrier deck the force of a catapult boost to the platform and weapon system on take off and rapid de-acceleration of a tail hook arrested landing increase strength requirements. Also naval countermeasure systems are often stored on deployed ships where physical strength requirements are higher due to the more hostile corrosive and physical environment of a sea-going vessel.
The Navy has historically used cylindrical decoy flare containers while the Air Force and Army Air Corps used rectangular or square flare cases. Now when faced with increased standardization requirements between the services, the Navy is required to adapt some of the square or rectangle flares for naval use and these standardized flares must pass stringent naval safety and handling testing. Past testing of rectangular or square cased flares exhibited the end caps lacking the strength to contain the energetic material under the increased naval requirements. Various means to increase the push out force on the end caps have been tried and tested but generally increasing the push out force necessary to open the end cap also increases the pressure necessary to properly release the encapsulated payload when the impulse cartridge fires.
Staking, side crimps and end cap tabs have been tested as a possible solution to the problem but all have failed to increase the push out force required for naval testing parameters without increasing the vulnerability to water intrusion and corrosion. Pinning can meet the increased push out force but creates holes in the flare case that exacerbates the entry of water and increases damage from the corrosive naval operating environment and increases assembly costs. Magneforming has shown promise as a possible solution but is prohibitively expensive.
Consequently, a need remains for a reliable, safe construction technique for square, rectangular or cylindrical decoy flare cases which exhibit the increased push out force required for naval testing parameters while still meeting the release requirements upon firing, that is not prohibitively expensive.
An object of the invention is to provide an improved decoy flare of rectangular or square construction that increases the push out force necessary to keep a payload containment cap in place and thus avoids releasing the payload without firing the flare.
Another object of the present invention is to teach a standardized case for energetic infrared, visible light or electromagnetic flares that meet all services testing requirements.
Another object of the invention is to provide a flare case that avoids water intrusion apertures and thus increases corrosion resistance.
A still further object of the present invention is to provide a case improvement for square or rectangular flares that allows decoy flares produced by the various United States and NATO military services to pass the differing service test requirements for safety, ease of release, interoperability and standardization.
A further object of the present invention is to teach a flare case and payload containment cap for variously shaped flares that can be sealed with a sealant to reduce the possibility of water intrusion.
Another object of the present invention is to teach a decoy flare that has the increased strength necessary to avoid accidental release of the payload during storage, handling, and carrier operations without prohibitive increased manufacturing costs.
A further object of the present invention is to teach a case construction that can be employed in the new decoy flares currently under development, e.g., the MJU-53/B and MJU-61/B being designed for cross service use.
Still another object of the instant invention is to disclose a decoy flare that can pass the demanding safety and corrosion testing for naval shipboard operation without increasing the force required for releasing the payload containment cap beyond allowable levels upon firing the flare.
Another object on the instant invention is to teach a payload containment cap and means of affixing the cap within a flare case that allows for placement of the payload containment cap at any depth within the flare case thus accommodating different size payloads in a standard flare case.
A further object is to teach a flare case and payload containment cap that can be firmly held in place at any point within the flare case by indents impinged into the case whereby the payload containment cap is firmly affixed between indents and movement both outward or inward is avoided.
In accomplishing these and other objectives and features of the invention there is provided a cylindrical, rectangular or square flare case that uses a payload containment cap held in place by crimping the case at one or more corners or at measured spacing around a cylindrical case. One variation presses the case inward at one or more of the case corners to extend over the top of the payload containment cap, resulting in an increase of force required to force the cap off and release the payload. Another variation indents the case at one or more of the case corners in a way that the case is deformed inward and over the top of the payload containment cap thereby increasing the internal pressure necessary to force the cap off of the flare case. Another embodiment using a cylindrical case flare places crimps at a 120 degree spacing around the top perimeter resulting in three crimps per case. Still another embodiment of the present invention uses pairs of indents impinged in place at a desired depth in the flare case thus holding the payload containment cap from moving outward or inward, and allows placement of the payload containment cap at any distance within the flare case. The depth of the indenture or corner crimp may be varied so as to regulate the pressure required to jettison the end cap upon firing of the impulse cartridge when the flare is used. In general, cylindrical flares with standard end caps result in a higher internal release pressure found adequate in naval safety testing but the teachings of the present invention could be easily adapted to a cylindrical flare case where one wished to increase release pressure required to remove the end cap. The construction of flare cases taught by the instant disclosures can be used with silicone or other sealant known to those skilled in the art to reduce the possibility of water intrusion and increase corrosion control. It has also been shown advantageous to place a rubber pad between the payload containment cap and the payload thus reducing abrasive wear or shock in handling and storage.
The corner crimp technique is a new feature considered an advantage over most existing crimps in that they will retain heavier payloads in rectangular and square cases. The corner crimps also withstand environmental and durability tests without problems. The crimps are easily adjustable. The retaining force can be adjusted by changing the crimp angles and depths. The tooling required to produce the crimp is inexpensive and can be teamed with hydraulic, air or arbor presses.